Properties of NiO sputtered thin films and modeling of their sensing mechanism under formaldehyde atmospheres

Castro-Hurtado, I.; Malagù, C.; Morandi, Sara; Pérez, Noemí; Mandayo, G.G.; Castaño, E.

doi:10.1016/j.actamat.2012.10.024

Cited by 65 publications

(36 citation statements)

References 42 publications

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“…42,43 Figure 7a It is known that, compared with the n-type metal oxide sensors, in p-type metal oxide sensors, a high response to reducing gas is relatively difficult to achieve because the chemoresistive variation of p-type metal oxide under sensing is relatively small compared to that of n-type metal oxide gas sensors. 38 Therefore, the improvement of gas accessibility, sensing area, and gas reaction resulting from the change of the hole accumulation layer of p-type metal oxides would be good ways to improve the sensing performance of gas sensors.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Sun

Wang

et al. 2015

J. Phys. Chem. C

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This paper reports the effect of mesoporous morphology and metal doping on the gas-sensing behavior of ordered mesoporous nickel oxide (NiO) materials. NiO samples with varied porous periodicity have been successfully synthesized via an improved nanocasting method. TEM, SEM, SAXRD, XRD, and nitrogen physisorption techniques are used to prove the presence of different mesostructured periodicity, as well as crystallinity, particle size, and pore size distribution of the as-synthesized NiO. The gas-sensing characterization indicates that the ordered mesoporous NiO with a long-range mesoporous periodicity based gas sensor exhibits a better ethanol sensing property than that of the ordered mesoporous NiO with short-range mesoporous periodicity. This result is due to the large specific surface area with sufficient sensing active sites, appropriate pore size distribution for enough gas diffusion, and proper particle size for effective charge accumulation of ordered mesoporous NiO with long-range periodicity. Furthermore, metal element doping, including Fe and Co, is used to adjust the sensitivity of the ordered mesoporous NiO based sensor. By doping of the Fe element on the optimizing mesoporous NiO, the gas-sensing property was obviously improved. The reason for that is attributed to the mesoporous structure and surface chemical state changed by the doping of Fe, resulting in more gas adsorption, diffusion, and reaction and attaining the enhanced gas-sensing performance.

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Section: Resultsmentioning

confidence: 99%

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Sun

Wang

et al. 2015

J. Phys. Chem. C

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“…The response of the gas sensor was linearly fitted on the increased concentrations, as shown in Figure (b). The CuO‐500 prepared from Cu‐MOF, exhibits a strong response to HCHO when compared to the other p ‐type semiconducting materials, such as CuO nanocubes, NiO powders, NiO nanosheets, NiO hollow microspheres, and Co 3 O 4 nanocrystals (Table ) . This result can be explained on the basis of diffusion behavior of the gas molecules.…”

Section: Resultsmentioning

confidence: 95%

Transformation of CuO from Cu‐MOF Templates and Their Enhanced Sensing Performance for HCHO

Kang

Park

Lee

2016

Bulletin Korean Chem Soc

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In this study, porous CuO samples were prepared from Cu-Metal-organic frameworks (MOF) templates through thermal decomposition. Four types of porous CuO samples were prepared through different decomposition treatments at temperatures ranging from 400 to 800 C. The prepared CuO samples were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction. The CuO prepared at a calcination temperature of 500 C (CuO-500), showed outstanding sensing performance in terms of response and response/recovery speed. The micropores in the material provided numerous active sites whereas the mesopores functioned as passages for the HCHO gas molecules. Furthermore, CuO-500 shows an excellent selectivity to HCHO gas.Keywords: CuO, Gas sensor, HCHO, Metal-organic frameworks Gas sensors based on metal oxides have been widely investigated for their suitability in the detection of toxic gases and organic vapors. The chemisorbed oxygen species on the surface of these sensing materials interact with the gas molecules. This results in changes in the electric resistance of these semiconductor gas sensors.1-3 In order to improve sensing properties such as response, response/recovery speed and sensitivity, substantial efforts have been devoted to syntheses of particular structures (such as hollow, urchin and porous structure) that can increase the surface area of the metal oxides. [4][5][6][7][8][9] Among these structures, the porous structure in the sensing material provides considerable advantages in terms of gas diffusion. This occurs because the gas molecules can pass between grains through pores, leading to considerable resistance variation in the sensing material. [10][11][12] In this regard, the Knudsen diffusion is suggested through various investigations as the most persuasive model. It is proven that mesopores are ideal sites for gas diffusion. 13 However, the development of simpler and easier methods for the preparation of mesoporous structures of metal oxides still remains a challenge.Metal-organic frameworks (MOFs) are a burgeoning class of porous materials consisting of metal clusters and organic linkers with large specific surface areas, high porosity, and chemical tunability.14-18 Because of these advantages, they have been investigated extensively for various applications in gas storage, sensors, catalysis, and drug delivery. [19][20][21][22] Recently, MOFs have been used as sacrificial templates during the thermal decomposition of organic linkers and the formation of metal oxides for the preparation of new porous materials. This approach turns out to be a facile method for the synthesis of porous metal oxides, using only thermal decomposition. [23][24][25][26][27][28][29] Decomposition conditions, such as temperature, speed, and atmospheric environment, play key roles in control of structure, porosity, surface area, and grain size of the transformed porous metal oxide. During the thermal decomposition, the organic linkers are changed to carbonaceous materials, resulting in th...

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“…37 In order to confirm the assumption, the nickel vacancy densities in the SC NiO and the PC NiO are characterized by XPS measurement according to the contents of divalent (Ni 2+ ) and trivalent (Ni 3+ ) species in NiO.…”

Section: Comparative Study On the No 2 Sensing Mechanisms Of The Sc Nmentioning

confidence: 99%

Effect of Grain-Boundaries in NiO Nanosheet Layers Room-Temperature Sensing Mechanism under NO₂

et al. 2015

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The discovery of gas sensing properties of single-crystalline nanostructures comparable or even better than their polycrystalline counterparts has triggered the attention of the gas sensor research community. To eleborate the sensing mechanisms of single-crystalline and polycrystalline nanostructures, the single-crystalline (SC) NiO hexagonal nanosheet and the nanoparticle self-assembled polycrystalline (PC) NiO nanosheet were prepared for room-temperature NO 2 sensing studies. The gas sensing studies revealed that the SC NiO exhibited a remarkably higher response to NO 2 at room temperaure than the PC NiO. The correlation between the structural features of NiO and the room temperature NO 2 sensing performances was discussed in detail via the grain boundary scattering theroy. It was found that the scattering potential played a vital role in the sensing process. Since the absence of grain boundary in the SC NiO reduced the NO 2 chemisorption-induced carrier scattering at interfaces, the SC NiO performed the largely enhanced sensitivity. Here we hope that this work can help us to further understand the gas sensing mechanism, and open up a new generation of gas sensors.

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Properties of NiO sputtered thin films and modeling of their sensing mechanism under formaldehyde atmospheres

Cited by 65 publications

References 42 publications

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Transformation of CuO from Cu‐MOF Templates and Their Enhanced Sensing Performance for HCHO

Effect of Grain-Boundaries in NiO Nanosheet Layers Room-Temperature Sensing Mechanism under NO₂

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Properties of NiO sputtered thin films and modeling of their sensing mechanism under formaldehyde atmospheres

Cited by 65 publications

References 42 publications

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Enhanced Gas-Sensing Performance of Fe-Doped Ordered Mesoporous NiO with Long-Range Periodicity

Transformation of CuO from Cu‐MOF Templates and Their Enhanced Sensing Performance for HCHO

Effect of Grain-Boundaries in NiO Nanosheet Layers Room-Temperature Sensing Mechanism under NO2

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Effect of Grain-Boundaries in NiO Nanosheet Layers Room-Temperature Sensing Mechanism under NO₂